Using inverter type motor drive devices, electrical motors can be controlled more freely. Both power and speed can be controlled using such devices.
However, controlling power of electrical motors often require significant currents, especially for low voltage battery operated systems, whereby even relatively small physical distances inside an inverter affect the performance of the motor drive device.
One way to reduce the effect of parasitic impedances is to arrange power switches of the motor drive device radially around the power output.
U.S. Pat. No. 7,248,483 presents an electrical power circuit assembly where bus bars are used between an insulated metal substrate (IMS) printed circuit board (PCB) and a fibreglass PCB. This provides a low parasitic inductance between surface mounted semiconductor power devices on the IMS PCB and filter capacitors on the fibreglass PCB. However, this solution still provides high currents which need to be handled in the assembly.